Pusher



- I, NW v Nov. 14, 1944. s. B. MARTIN I 2,362,494

PUSHER Filed June 12, 1942 3 Sheets-Sheet 1 I STODDAE'ID Jam/warm we g BY \f Arrore/va s NOV. 14, 1944. 5. N

PUSHER Filed June 12, 1942 3 Sheets-Sheet 2 INVENT OR. STODDA ED .5. MART/N ATTORNEYS 4 Nov. 14, 1944. Y s. B. MART IN 2,36

PUSHER Filed June 12, 1942 3 Sheets-Sheet 3 A rrozwz-vs pushers as master pushers.

Patented Nov. 14, 1944 I Stoddard B.

sapiiaaonnne z,1942; SerialNo. 446,754

- 15 Claims.

:This invention relates to improvements in'stock the type employed :in

feed fingers or pushersof automatic screw machines.

Each spindle of an automatic screww machine ordinarily surrounds a rotating'collet tube having a a collet at its forward end which is arranged to of stock fed axially; through the tube. At the end of each cycleof operation the projecting end of stock is cut off from the bar, -'whereupon the collet opens andav new length of stock is: fed

the stock and repeat the cycle ofoperation. The stock is ordinarily fed forward by a pusher carried by a reciprocating'pusher tube arranged bebar of stock. I o I In the conventional machine. the pusher is simply a springbushing exerting a constantlgri'p on thebar of stockwhichis moved forwardly, after the collet opens until the forward end of the bar strikes a stock gauge; Thecollet then grips the barand the pusheris retracted. ,One, of the disadvantages of this arrangement is that"'when 'the pusher is given a'suiiicientlyftightgrip on the bar'to insure accuratefeeding and prevent rebounding when the bar'strokes the gauge; there fisdanger' of scratching or scoringthe stock when the pusher is retracted, Another'disadvant'agelof .such an arrangement is'that the pusher exerts a constant grip onthe barstock during both xth'e feeding and return strokes so that ithegripping surfaces of the pusher are rapidly worn out by the friction of the return strokes.

To avoidthese disadvantages it hasbeen proposed to provide jone way' grippers which by a wedging or similar action'grip the; bartightly on the forward feedingstroke and release it, tr grip it but lightly,-on the return stroke. Pushersof this type aredisclosed in-my prior Patents Nos.

2,088,067, 2,169,107, 2,187,089, and 2,187,090,:ifid

in my co-pending application'Serial No. 387,476,

be compressed radially to grip and rotate a bar forwardly and the collet is again closed to grip tween and-coaxial with the collet tube and the within the radial extent of. the shell wall with filed'April 8, 1941, now Patent N0. 2,323,067, dated t I June 29, 1-943, and applications Serial No. 390,601,

filed April 26, 1941, andSerial No. 406,268, filed August 11, 1941.

It has also been proposed to construct such The gripping surfaces that en'gagethe stock are provided with a bushing removable from the pusher shell, so that -.a bushing with the desired sized opening may be "po'sitioned in the shell of the pusher to accommo- 1 date any particular size, of stock without substitutlng an entire pusher or feeding finger as has been customary in; conventional machines, Such master pushers} are bf but 'liniitediutility unless the construction issufiiciently compact and simple tofpermit thefs'ame to be used to feed stock addition to smaller sizes of "stock; [Oneof the difliculties heretoforev encountered of the maximum capacityfof. the machine, in

in connection with'masterpusher's having a oneway' gripping action arises'fronif the fact that it is occasionally necessary to withdraw the bar. be-

ing 'workedupon from the machine. In'pushers in which the gripping action is increased by wedging means; and the likeon the feeding stroke,

it is neces ary-w provide means to prevent the wedging or tight gripping action when the bar is withdrawn; The provision of suchmeans in addition to the wedging means not only increases the cost, and complexity of the device','but-adds tothe difficulty of maintaining it sufficiently compact to permit the same pusher tohandle'all sizes of stock up'to and includingthe'maximum capacity-ofthe'machine.' p

The present invention relates particularly to the subject matter disclosed in my co-pending application Seri'aLNd 390,601, filed April 26,1941,

of which this application is in part a continuation.

l -Th'e principal objectsof this' invention are to arrange .withinthe' thickness of the wall of the shell of the pusher a suitable abutment means to pull the bushingon itsiretracting stroke in a mas 'ter pusherxof-vthis type: to combine a wedging means to increase the grip of the bushing .on the stock on the feeding stroke which is arranged retracting abutments which are .alsogdisposed Within:thethicknes'sof the' shell wall, so. as to minimize the necesary radial thicknesstof the entire pusher .to. accommodate stock of the maximum capacity of:the; machine; and to maintain the retracting abutments in engagement with each other at all-time's, whether or-notthere is a bar of stock disposed, within the 'bushing,

Anothen object; of -thepresentinvention is to simplify and improve the construction of master pushers of this type in which removable bushings of "the-desired size areheldin place-in a pusher shell so that atight gripping force is exerted on the stock during the feeding movement of the pusher and asrelativelylight force is appliedduring,- thev retracting stroke, the pusher H including readily .manipulable means to prevent the application of the tight gripping force, when-desired,

to permit withdrawal of the'bar of stock. Other objects are to simplify andcheapen the construction of the bushing. so that the same may be'readi in ta led -removed; toi:;di ppse the opera- I of the pusher shell;

tive parts of the bushing in a relatively shallow depth to permit the use of a bushing having adequate strength and bearing areas for stock of the maximum capacity of the machine, and to arrange the means for preventing the application of the tight gripping force during withdrawal of the bar of stock in such a manner as to prevent its accidental application from over-running of the pusher shell after the collet has opened at the beginning of the feeding stroke. Other objects and advantages will appear in the following detailed description of prefered embodiments of the invention.

In the accompanying drawings:

Fig. 1 is a side elevation of one form of pusheiembodying this invention;

Fi 2 is a section taken on the line 22 of Fig. 1;

Fig. 3 is a section corresponding to Fig. 2 but Fig. 5 is a wheituairrarseeon tissues the bushing "of Fi gilrmovedfrorn the pusher shell,

the relation or he p'ar't's'tmg' exaggerated to i1- lusfirate th 'j fi i Fig. 6 is a detail sectional view'taken on the line 9. r s

Fig. 7 is a perspective view of one iforr'nof looking key suitable fo r fise with anygof th modifications illustrated;

8 is a s ctiened if sfii eil nez i -fff ln' aing a slight modification in the arrangement of e c ey;v Fig. 9 is aside elevation corresponding to F i 1 illustratinga modification in the construction Fig. 10 is a cross section taken on the line |0 lBof'Fig.9; a v, I

Fig. 11 is a side elevational view of a further modification embodyinga bushing split three ways;' v

Fig. .12 isa section'onthe line l2-l2-of- Fig. 11; Fig. 13 is a'-'section'of-the locking-keyof'Flgs. Hand 12-; r 1

. Fig. 14 isaside elevation partly in-section ofa further modification of the invention;

Fig. 15 is a cross section taken on .the-line I5l5'of Fig. 14; Fig. 16 is a view of 'theoppositeside'of.*theshel1 shown in Fig. 14; i

Fig. 17 is a longitudinal: section "through the bushing shownin Figs.-14 and 15.

Fig. 18 is a view partly in section and partly in elevation of a shell of a further modified form-oi the'invention;

Fig. 19 is a 'cross section takensubstantially Fig. 20 is aside'el'evation oiabushingto-cooperate with'the' shell shown in'Fi 1 Fig. 21 is anend view of the bu'shinglodkin'g in the direction'ofthe arrows 2:f=-2l -'of Fig'.* 20;

Fig. 22 "is a'view of 'theoppo'site'endlooking in the direction'of the an mia-22 of Fig. 20;

Fig. 23 I is a view partly in elevation and {partly in section of the shell and hushi'ng assembled with the wedgin'g surfaces-"engaged to tightlyg'ri'p the stock; 1

Fig. 24' is a partial ioiigitildiiial lictioii taken substantially on the lin e 25:24 on Fig. waterin in the"directioniif tlie'farr'ows;

Fig. 25 isa cross-sctionqtake'rr slat-simian on the line 25-25 of Fig. 24 looking in the direction of the arrows;

Fig. 26 is a side elevation of the assembled pusher with a part of the shell broken away showing the wedging surfaces out of engagement; and

Fig. 27 is a partial side elevation corresponding to Fig. 26 but showing the bushing turned to prevent engagement of the wedging surfaces.

Referring first to the construction shown in Figs. 1 to 6, the improved "pusher includes a shell 20 arranged to be secured to the forward end of the pusher tube of an automatic screw machine or the like. The thickness of the shell is reduced near its forward end by a counter bore 21 and the shell terminates in a forward wedging end 22 cutzgoack slightly on opposite sides as indicated at I tubular bushing is out longitudinally through its length and through the thickness of its opposit'e side's forming "two semmyimdmai r'n'e'rrifiers "2'4 and 2'5 separated by oppositely disposed splits 2B. Near its forward end ash'al1owgro'o've '21- is "mesqu te hushing to'receive a 'springj28. Shoulders 29'ai1d30 attire opposite sides "of Y the grtave serve to retain the spring in position. Rea'rwardly from'the shoulder' 30 the ester wall "or the bushing-is ret rees in'aiidnical shape 31 rtaiungew agmg s'urra'ce adapted'to co ac't with tl'ie fo'rwa teasing 'ed'ge '22 of the 'shell mm- 'rea'setlie'grip of' the bushing *o'n the stock. To "the re t: thecldnical surfacedl ashal l'owg'roove is turned in the esreno'rsiirraeear the bush- I fI lieslill nis forind1none side with an Ofilii'ng -33" defined by a r ea'rwardly facingfstraight edge 34, an axially extending straightside edge -a5,*a1nirw'ara1yrating ge as n a notch a1 fermenting 'in a beveled "edge "38, the notch 3'l io'e'ing' a'li'griedwith the frearwardly' facing edge 34 fandhaving a ftfrwardly fa'c'ing edge "48 spaced "froin'thefedgeifi. r

4 & j key'lfl is arrangedto'l'ok'the bushingin'the sheu. in the rd'rinjiliiistfated inthe Figs. 1 to 6 =45 mass ve the key lll 'i's made from resilient or I I" able material and includes "an "ei'r'uate port an' ar'dl' mines-"errata. ""Aslotffl'is formed "in 'thefiu v g sctio'n 24'aciossfthegroovehfto receive 'theiriwardiif juiriie'e end 142 or the lieywo. The opposite e'n'd ofthefky consistsof an arcuate thickened earner-114 having a thickness "its? forward sewage-tithe narrow ledge "B6 of f" l thickness'aisthe portionilfa'sillustrated The bushingis assembledwithin'the shell b'y sizriply tes n 7 1t axially into "the open end or "tlie'sliiell 'tvith "t'heklot-WS {timed to "be expose t5 tiiroii'eh the openin as. The" i wsr'aiy turaed hand end of the opening 3'3. .motionof the shell causes the end 22 ofqthe shell to engage the taper 3|, increasing the grip of the bushing upon the stock and causing the .bushing, and therefore the stock, to mov'ezfor- -ward with the pusher tube. With thebushing .of the type illustrated, divided intotwo parts ,by the splits 26,- the parts are arranged so -that .within the opening 33 in the shell. .jsrtherota- .tion .of the bushing is continued the. shoulder 41, formed at the junction of. the thickened portion 44 with the thin portion 4 I ofthe key,.en-

In operation, the stock is normally rotated in a .a counter-clockwise direction .whenthe ,collet ,carriedby the spindle grips the stock.-v When the .collet opens, the pusher tube is'moved. forwardly,

or to the left as seen in Fig. 1, to advancea new .length of stock S through thecollet.i As theishell 5.20 moves to the left the right hand portion of the opening 33 moves to the left with respect to the bushing until the key 40 enters the right The advancing when the shoulder 4'? is .in its normal position in abutment with the side edge 35 of the opening in the shell, the wedging forceis first applied to the bushing on the diametrical planeperpendicular to the plane defined by the splits 26. The forward edge of the shell is cut back slightly, as

indicated at 23, on each side between the ends of the diameter perpendicular to the plane .of

the splits 26 so that these out back portions do not engage the wedging surface 3l until after considerable pressure has been applied by the projecting portions of the forward edge 22.

At the completion of the feeding stroke the .stock is again gripped by the collet and the pusher tube is retracted. The retracting movement of the shell 20 causes it'to slide rearwardly,

or to the right as illustrated in Fig. l, ,with respect to the bushing, until the rearwardly facing edge 34 of the opening 33 passesover the ledge 46 on the key 43, and engages the forward; edge of the thickened portion 44 of the key. Since the ke is seated in the annular groove 32, and j the thickened portion 44 spans one of ,thesplits 2B, the retractingmovementof the-shell, 20 is then transmitted to both sections 24 and 25 of the bushing. The initial portion of the retracting movement of the shell 20 releases the wedging pressure applied by the engagement of the edge of the shell 22- withthe wedging surface 3| so that the bushing engages the stock withonly the relatively light grip provided by the-spring 28, and thus there is nodanger of marring the stock while the bushing slides over it on ,the .retracting stroke. v I

When it is desired to remove the bar of stock from the machine, it is only necessary to effect relative rotation between the bushing and the shell in the direction opposite to the normal rogtation. so that the thickened portion .44 of the ke 40 enters the notch 31 in the opening 33.

The bar may then be pulled rearwardly and the engagement of the thickened portion 44 of the key with the forwardly facing edge 48 of the notch 37 prevents the bushing from moving rear- .wardly in the shell a sufiicient distance to cause engagement between the forward edge 22- of the shell and the beveled surface 3| of t'he hing. iv Thus the bar may be pulled out of the machine against the friction provided .by the spring ;28.

vthe parts is sufi'icient to make it diflicult to turn 'th e bar byhand, the 'collet ma be closed on the .stock soas to hold it against rotation,. and the pusher tube rotated by a spanner wrench or the liketengaging its rearward end to bring; the key .into the notch. In case there is sufficient fric- 'tion to prevent a straight withdrawal of ;the bar from the pusher tube, the pusher tube and bar may be slammed rearwardly until the pusher tube engages the stopfat the rear end of themachine so that the bar continues to move lybyits own inertia. Whenvit is desired to remove thebushing from the shell 20, the pusher tube is first removed from the spindle and the projecting end of the bushing is rotated in a clockwise direction until the beveled edge '45 of the key 40 engages the ,beveled edge'38 of. the opening 33. Continued rotation of the bushing with respect toth-e shell causes the beveled end of the key .to ride over the beveled edge 38 on the shell so that-the' key is forced to the outside of the shell. As; soon as the bushinghas been rotated far enough to bring the": groove 43 into alignment with the opening -33, the key 40 drops outand the bushing may be I spect to the opening 33 in the shell.

pulled forwardly out of the shell 28.

, 'I'he splits 26. which divide the bushing into the two parts 24 ,and 25 are preferably flared out slightly atthe forward end of the bushing through .about the axial length of the groove 27, as illus trated at 49. Likewise the groove 21 is preferably formedslightly deeper atits rear edgethan at'its forward edge, as illustrated at 50. Thus of the key 4.0 in position to engage the edges of the opening 33, regardless of whether there is any stock disposed'within the bushing. Preferably theforward face of the bushing .is formed with a slight bevel 5| leading to the internal bore in the bushing,.to make certain that the force spring 28 will keepthe rear end of the bushing {spread outwardly into contact with the shell; even when the extreme end only of a bar' is gripped by I .the bushing near its forward face and no new bar has been fed into the machine. Even though in such circumstances the wedging action on the feeding strokemight first force the rear ends of the bushing sections 24 and 25 together,; the action of the spring 21, as soon as the pushershell .20 starts its retracting stroke, will again force.

therear ends of the bushingsections outwardly so that the key 40 is inproper positio Fig; 7 illustrates a key I40. which may tee :ply and easily manufactured and which maybe used in any of the embodiments of the inven- -tion. The key I is made from a strip ofmetal, having a thickness equal to the depth of the groove 32, which is cut to form a portion [4| of a widthie'qual: to the axial extent of the groove rearwardofthe' n with re qmfidaslightlynarrewerportion l44. menarrowerportion 444 then b'en't through 18'0"at the point 145, so'that the narrower portion 144 overlie'sthe'portion14L The two portions may then' bespot-welded togeth'er; asindicated ati 50,

"or secured in any otherisuitable manner. The endofthe narrower portion 444 forms the abutm'ehtshoulder 14! to limit the rotation of the iiiishihPwith re'sp'ectto the shell, and the bond 45 hassuflicient radius to cooperate with the bevelededg'e 3'8'in the shell to permit'the removal of t-he key. 'The edge of the portion -l4l which' is not covered by the portion 144 forms the ledge ii. The end of the portion I4I opposite the 'lqend 415 is turned downwardly to form theflan'ge 14-2 to engage in the slot 43 in the -bushing.

-Another slight modification in the'arrangem'ent of the key is illustrated in'8. In this 'embodiment the key 240 is formed with a thin pornon 241 of 's'ufiici'entlength'topermit the downturhed end 242 to engagein one'of the splits 26in "the bushing. The entire key is made slightly morethan 180 in extent so that the thickened portion 244 "spans the other'sp'lit 26 and thus transmits theret-ractin'g' motion to both sections 24 and'25 of the bushing as in the embodiment "previously described.

A modi'fied construction of the shell is illustrated in Figs. 9 and 10. In this embodiment the shll l20 is formed with two oppositely disposed splits 'IGU extending axially into the shell from "the forwardedge thereof,preferably'for-a greater distance than 'the'len'gth of thebushing disposed within 3 the shell. 'The two sections of the' shell so that the shell normally exerts a spring tension on the "bushing and thils on the stock. in "this arrangement thespring' fl maybe omitted in some "instances, since -'sulficient itension' may be obtained from the shell alonen fioweven when the spring '2 8 is also used-the flaring of the splits 26 in the bu'shin'g, as illustrated at '49, maybe "omitted since when nost'ockis disposed Within the pushing the --shel1' collapses 'inwardly with ithe "bushing, retaining the desired relation-of the key 40 and the opening 1'33 at 'all times. In this iorm of 'the inv'erition theshell may befoimed siinply'with a-redtarigular openin H533 to 'receive the key 40 without providing a notoh to Iieng'alge hashing i's'diVided'ilito thre sectibrls "324 by three equally spacedsplits-flfif "l he fo'rward edge 3322 "ofthe shell 320'i's arranged in-=a rplane penpendiciilar to the a'xisso as *to engag'e the beveled 'suffa'ce fl I on the bushing throughoutfthe rentire circumferencesimultaneously. Sincesthe hushi'ng -is'-divided intofmore" than two parts there is nomecessityei appiymg the wedgingiotce I in afisingle planeas isprererable withhthe l s eamer.

embodiment illustrated in Figsii toifi. The openin'g'MBfinthe shell-and the key 340 are also some- --what difierent1y-- arranged in 'this modification. The "key 340 is provided with a thin portion 341 ot sufilcientcircumferential length to extendtwothlrtis' "of the distance about the bushing so "that down-turned end 342 engages in one ofthe splits 326, the thickened portion 344 spans ran- =-other of the splits 326 andthe third split 326 'isspanned by'the thin portion 34! of the key. EI'hus an of thesections of the bushing arefirmly lield iagainst axial movement relative to each "other.

Tlreppening333in the shell is formed with .a .'notch"33'l to receive the'thi'ckened portion'344 oi the key sllluwhen thei'stock and bushingare turned in the'idirecti'on oppositeto "the normal rotation rrsosthat the .;forward edge .322 of the-shell is prevented irom engaging the beveled surface salmon the bushing when it is desired to remove :the bar :Iof stocks. The notch 331. terminates ina :bev- --ele'd edge 3'38mhi'chcooperates with the beveled edge 345 On the key 340 to facilitate removal :of the "key in :the same manner as the beveled edges =38 and 45 in the embodiment disclosed iniFigs, 1 to 611inclusive.

T-he opening 333in'the shell has its notch 33'! spaced from both the rearwardly facing edge 334 andthd-forwardly facing edge 336 of the opening. Thus when the shell moves on its retracting stroke the thickened portion 344 of the keyis sea-ted against the-edge 334 and cannot enter the notch- 33'! by accidental relative rotation between the bus'hing and the stock in the direction'oppo- "site tothe normal direction of driving, which -=might occur from the shell over r-unning the stock and bushing. Proper positioning of the thickened portion344 is insured by the fact that the-stock is gripped and rotated by the collet during the retracting stroke of the pusher, =so thatthe 'shoulder 348 on the key is'strongly urged against the'edge 335 of the opening. -At the beginning of the' pushing stroke, if it should happenthat the-colletreleases the stock before the shz'ell filllmoves forwardly. the shell cannot over- "run-'and-position' the thickened portion 3440f the key the"notch331,"and thus lock the wedging surfaces outof engagement. As soon as the shell 32'0' begins to move forward the notch 331 is *movedrapidly past the end of the key and'the "iorwardedge 322 engages the wedging surface 331. Any slight relative rotation of the bushing 'a'ndthe shell during the beginning of the forward stroke uritilthe Wedging surfaces come into engagement is taken care of my making the edge illiii o'fthe opening slightly longer than the edge 3"34 so that thekey cannot enter the notch during-this"initial'portion' of the forward stroke of the pusher. It will be-und'erstood, of course, that the arrangement o'f 'the key and the three split bushing illustrated in Figsfll to 13 may be'used with -either a solid shell, as illustrated,'or with a'split or inwardly tensione'd shell, suchas that shown in Fig. 9, and likewise that the arrangement of '--the-'opening"3'33 and the'notch 331 may be used *with any of the-other forms of bushings andikeys. Another slightly-modified embodiment of the 'invention is illustrated iniEigs. 14120 17 inclusive.

In thisembodiment the shell 420 is formed with "two *similar oppositely disposed openings 433 arranged'to cooperate with;=.a:pair :of oppositelydis- -=pose'd -keys 440. ln :the: particular embodiment illustiat'ed lthe xshellilisrformed with one split Ell extending from the *front face: intoone of the openings 433 to impart a certain amount of r'e-- vsiliency to the forward end of the shell.

front edge of the shell is formed, with wedging- The surfaces 422, one of which ispreferably intersected by the split460, these wedging surfaces being separated by cut-back portions 423 of the forward edge. e I e r The bushing illustrated inconnection with this embodiment is a one-piece bushing comprising the partially separated sections 424 and 425. On

one side a slot 426 is out completely through the length and wall thickness of the bushing, and on the opposite side a s1ot'426a' is cut through the'thicknessof' the wall of the bushing and through the major portio'nfof its lengthjleaving the two sections 424'.and 425 integrally connected by the portion 4261i at the end of the slot The bushing is formed on'itsexterior surface with a wedging surface 43!. In advance of this wedging surface a ledge 42'! may be provided if' desired for the reception of a spring; Normally,

however, no spring is. needed on the bushing; since afterjbeing constructed it is'inwardlyten sioned to partially close the slot 426 and the forward end of the slot 425a. v V

Each of the keys 440 is formed with a thickened portion 444 terminating in a beveled edge- 445 for cooperation with the beveled edge 438 of 5091 An annular spring 5! 0 is seated between the 'iibs 50! and 508 and an annular spring 5!! 1 is seated between the ribs 508 and 509. n

The bushing is provided with one or more milled slots'5l8 extendinglongitudinally and arranged to receive a key 5!9. As illustrated three slots 5l8 are provided and are located so that they are cut through by the slots 506 which divide the bushing into three parts. i

Each key 5! 9 is rockably seated in a slot 5 !8 and is formed at one end with an extension 520 passing under the spring 5!0 and at the other end with an outwardly projecting head 52!; The extension 520 is formed with a notch 522 receiving and fitting the spring 5l0, sothat the keys are locked in their proper position by the spring.

The head 52! of each key 5l9 projects outwardly a slight amount beyond the outer surface of. the'bushing 502-and is positioned in one of the L-shaped cutouts 504 formed in the shell 50!. The heads 52! of the keys 5l 9 are nor- I mally positioned in the portions of the cutouts one of the openings 433. In addition'each key is formed with a thin portion of substantially the same thickness'as the depth of the groove 432' in the-bushing, the thin portions 43! terminating in inturned ends 442 arranged to seat in the slots 425 and 42601..

In'this embodiment the parts are assembled and operate in the same manner as previously described, except that both of the keys 440 "are simultaneously drawn into the space betweenthe bushing and the shell during assembly and the thickened portion 444 of each key engages the edges of itsv opening 433 so as to apply there-" tracting force to both sides of the bushing s'imultaneously. Preferably the two parts 424 and 425v of the bushing are tensioned inwardly only a slight amount adjacent the groove 432 so that they-do not move together sufficientlyto permit the" thickened portions 444 of the keys to-escape inwardly from the openings in the shell when no stockis gripped inthe bushing. It willbe ap'-'- parent that any desired numberof slots and keys may be usedin this form of the invention.

,A further modified form of; myinvention is illustratedin Figures 18 to 27 inclusive. In this form the pusher shell as in the embodiments previously described, is provided at its rearward endwith threads 503 to fasten the shell to'the pusher tube, and is provided at its forward end with a bevelled surface 5l3. Intermediateii'ts ends the shell is formedwith one or more L- shaped cutouts 504 providing both forward andcooperation with lateral abutment surfaces, for the bushing 502.

;As illustrated the bushing 502- is' divided into three segmental portions 505 by'longitudinal cut-sf 500. At its. forward end the bushing is provided with a thickened portion 5l6, the outer surface of which is bevelled at a small angle as'indicate'd' The thickened portion 5I6 may be at 5H. knurled to facilitate handling the same to remove thebushing lfl'hesections sush the bushing are preferably turned down at spaced points, leaving circurnier;

ential outwardly projecting ribs 501,"508and 52!" of the keys remain in the portions of the cutoutsr504 having, the greater axiallength and prevent relative rotation of the bushing and the shell. When it is desired to withdraw the bar from .the pusher the bar is pushed forwardly and turned ,in'a counterclockwisedirection so as to seatthe head fends'52!" of the keys 5l9 in the portiohsiof the cutouts 504 having the shorter axial length. .In this position, as illustrated in Figure 27, the heads 52! prevent relative axial movement of the shell and bushing and thereby prevent. .wedging engagementof the tapered sur face 5!! and bevelled surface 5l3.

When-the bar is removed from the pusher the sections 505 of the bushing collapse inwardly the amount permitted by'the slots 506. This col- ..lapsing movement would-be sufiicient'to' permit the ;heads52! of the keys 5|9 to escape from the 1 cutouts'504 if the keys were rigidly mounted on the bushing.. v However, when the bushing collapses; the extensions 520 of the keys 5I9 are likewise pressed inwardly by the tension of the spring 5;!0, forcing the heads 52! of the keys radially outward so that they remain engaged in the cutouts 504. I

'Topermit removal of the bushing from the shell the head ends 52! of the keys are-formed on one side with' 'bevelled surfaces 523. ,When the/stock is removed from the bushing the for-" wardthickened portion 516 of the bushing 502 may be graspedand the bushing rotated in the shell so as to turn the heads 52! intothe short portions of the cutouts 504,. and further rotated to r-engage the bevelled surfaces 523 with the edges of the cutouts 504 and force the head ends 52! of the keys radially inward against the tension of the spring 5!0. When this is done the keys clear the inner surface of the shell 50! andthe bushing may be withdrawn from the shell.

. "Although several embodiments of the invention have been described in considerable detail, it is r to be understood that the invention is not lim In normal operation the stock is.rotated in a clockwise direction as seen from the rear end of the spindle, so that the head ends tot e particularf atures ortha parti lar? com inationsof-io turosd sdo Fo -exams p the e. o e lust eie Fi 1 made,

from a singlestrip-of material may utilizedyin any or t e mlood m t shown; Similar different forms of b'llS hiIIgQ IQQ/Y'BQ; u other forms; of shells other-thanthose in; con,

nectionwith which they are described. of the features are likewise applicableto difier hell and bus n arranged to ncrease he rin fisa-id b sh ng on th stoc when: said-shell moves forwardly with respect to said bushing, said shell being formed with an opening through the wall thereof, abutment means: carried-by saidbushing and projecting into said opening, said abutment means being arranged to engage one edge of the opening in said shell, to move said bushing; rearwardly whensaid shell moves rear.-v wardly, and said abutmentmeansbeing arranged to engage another edge'of' the opening to restrainrelative rotation of said shell and bush ing in one direction.

21A pusher comprising a shell, a bushing adapted to. grip stock to be fed disposed within said shell,'cooperating wedging means on said shell-'andbushing arranged to increase the gripofsaid bushing on the stock when said shell moves forwardly with respect to said bushing, said shell being formed with an opening through the wall-thereof, abutmentmeans carried by said:

bushing and projectinginto said opening, said abutment means: being arranged toengage one: edge of the openingin said shell" to-limitrela-.

tive rotation ofzsaid shell and bushing in one direction, said opening being formed with a'notch ofasaid bushing on the stock when said shell" moves -forwardly with respect to said bushing,

said shell, being formed with an opening throughthe Wall thereof, abutment means carried by said bushing and projecting into said opening; said abutment means being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearirzardly,v said abutment means being arranged to engage another edge of the openin to limit rela tive rotation of said shell and bushing in one direction and said opening being formed with a notch opposite said lastlmentioned edge adapted to receive said abutment means upon relative rotation: of ,said shell and bushing in theopposite direction to prevent engagement of saidodsins m ans.

LA pusher comprising a shell,- a bushing,

adapted to resiliently grip the stock to be fed disposed within said shell, said shell being formed with an pen n Spa itearwanily f m its forward edge and said b lShing being formed with a recess arranged to-register in an axial H Q l iQIi ith id Qpfil liii W116i! Said bushing s-ass mb d n o era ive o i ion ithin; said h l; and a e engasedwith said hus i he; with:

aid ey o udin a port on a a ted o be disposed;

oil

aiiaiitd o-iesili n lr g i hoi t ok o o t e reoo s said; bushi g-o ig honoa brtbe a l oi said Sh ia aortionadanto -i n ioo l oia sa d b sh n into. the n oing; a, hell,

A pusher o mrrisine. a shol o bush rom ai fiistmont on sit on and a d to) udi g a, po t on da edv t pro ect rom aid. bushing into the opening said shell.

6- A u er mp is n a ell a buohins. adapted to resiliently grip the stock to be fed dis os d, ithin sa d Shel i said. s e l b in o me h a pen n ao r ara ly from, i or ward edge and said bushing being formed with arecess arranged to register ir -an axial direction with said opening when said bushing is as1 sembled in operative position within said shell, and a separate key, adapted to be inserted through said opening and engaged with said ush ng one re at ve r umferential os tion of said sh ng nd-she l said he nol idinea :n rti n dapt d t e isp se i the rece s,

n and t a d k ned porti n ou ft e ecess in aid bu h ng pon o tiv rotatio gir a d bushing a s l i he oppo te irection:

7. A pusher comprising a shell, abushing divided'into separate segments disposed within i h l a p n su ro nding the ments oil said bushing tov urge: the same inwardly upon stock to be fed, inter-engaging abutments on said-shell and bushing spaced axially-from said spring, the meeting edges ofsaid segments be; ing beveled from oneend of said bushing-ins. wardly to-a point adjacent Said Spring whereby when no'stock' is: disposed withinflthebushing the tension of said spring urges the beveled edges. of said segments, toward each other and the portion of said bushing carryingsaid abut: ments radially outward against said shell,

8. A pusher comprising a shell, a bushing divided into separate segments disposed? within said he a spring ur ounding t se men s Q a said bushing to urge the same inwardly upon stock to be fed, inter-engaging abutments on. said shelland bushing spaced axially-'- from said, spring, the meeting edges of said segments being flared outwardly away from eachiother from apoint adjacent said spring to one end-.oi-saiglyi bushing wh r by when. o ck is isposodwithin h 'b h ns he tension oi-soid riliis urges-i 7 other and urges the portion of said bushing carstock to be fed, cooperating wedging means on said shell and bushing arranged to increase the grip of said bushing on the stock when said shell moves forwardly with respect to said bushing, abutments on said shell and bushing spaced axially from said spring and arranged to engage when said shell moves rearwardly, the meeting edges of said segments being flared outwardly at one end of said bushing whereby when no stock is disposed within the bushing the tension of said spring urges the beveled edges of said segments toward each other and urges the portion of said bushing carrying said abutments radially outward against said shell.

10. A pusher comprising a shell, a bushing divided into separate segments disposed within said shell, a spring surrounding the segments of said bushing to urge the same inwardly upon stock to be fed, said shell being formed with an opening through the wall thereof, abutment means on said shell and bushing spaced axially from said spring, the meeting edges of said segments being beveled outwardly away from each other from one end of said bushing inwardly to a point adjacent said spring whereby when no stock is disposed Within the bushing the tension of said spring urges the beveled edges of said segments toward each other and urges the portion of said bushing carrying said abutments radiall outward against said shell.

11. A pusher comprising a shell, a bushing adapted to grip stock to be fed disposed partially within said shell, one end of said bushing projecting from said shell and formed with a wedging surface cooperating with the end of said shell to increase the grip of said bushing on the' stock when said shell moves forwardly with respect to said bushing, said shell being formed with an opening through the wall thereof, abutment said shell to move said bushing rearwardly when said shell moves rearwardly, and said abutment means being arranged to engage another edge of the opening to restrain relative rotation of I said shell and bushing in one direction.

12. A pusher comprising a shell, a bushing adapted to grip stock to be fed disposed partially within said shell, one end of said bushing projecting from said shell and formed with a wed ing surface cooperating with the end of said shell to increase the grip of said bushing on the stock when said shell moves forwardly with respect to said bushing, said shell being formed with an opening through the wall thereof, abutment means carried by said bushing and projecting into said opening, said abutment means being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearwardly, and said abutment means being arranged to engage another edge of the opening to restrain relative rotation of said shell and bushing in one direction, the end of said shell being slotted and formed to contract upon said bushing.

13. A pusher comprising a shell, a bushing adapted to grip stock to'be fed' disposed witha in said shell, cooperating wedging means on said shell and bushing arranged to increase the grip of said bushing on the stock when said shell moves forwardly with respect to said bushing, said shell being formed with ,an opening through the Wall thereof, abutment means carried by said bushing and projecting into said opening, said abutment means being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearwardly, and said abutment means being arranged to engage another edge of the opening to restrain relative rotation of said shell and bushing, said abutment means being constructed so as to be resiliently pressed radiall outward and to be yieldable inwardly to permit removal of said bushing from said shell.

' 14. A pusher comprising a shell having a circumferentially continuous forward edge, a bushing adapted to grip stock to be fed disposed within said shell, cooperating wedging means on said shell and bushing arranged to increase the grip of said bushing on the stock when said shell moves forwardly with respect to said bushing, said shell being formed with an opening through 4 the wall thereof, abutment means carried by said bushing and projecting into said opening, said abutment means being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearwardly, and said abutment means being arranged to engage another edge of the opening to restrain relative rotation of said shell and bushing, said abutment means being constructed so as to be resiliently pressed radially outward and to be yieldable inwardly topermit removal of said bushing from said shell.

15. A pusher comprising a shell, a bushing adapted to grip stock to be fed disposed within said shell, cooperating wedging means on said shell and bushing arranged to increase the grip of saidbushing 0n the stock when said shell moves forwardly with respect to .said bushing, said shell being formed with an opening through the wall thereof, abutment means carried by said bushing and projecting into said opening, said abutment means being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearwardly, said abutment means having a beveled side to engage another edged the opening to resist relative rotation of said shell and bushing in one direction, said abutment means being constructed so as to be radially yieldable and ar- STODDARD B. MARTIN. 

